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Indonesian B737 Crash, Part 3

Sun Mar 18, 2007 3:09 pm

Now that part 2 has nearly reached 300 replys, maybe its time for part 3, Indonesian B737 Crash Part 2 (by ANCFlyer Mar 10 2007 in Civil Aviation)
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zeke
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RE: Indonesian B737 Crash, Part 3

Sun Mar 18, 2007 4:01 pm

Someone care to do a summary of factual information and photos known to date ?
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mandala499
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RE: Indonesian B737 Crash, Part 3

Sun Mar 18, 2007 4:04 pm

Oh Boy... gotta write that damn amateur accident report of mine ! LOL

Mandala499
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RE: Indonesian B737 Crash, Part 3

Sun Mar 18, 2007 5:44 pm

High and fast for reasons as yet unknown.
 
NAV20
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RE: Indonesian B737 Crash, Part 3

Sun Mar 18, 2007 6:38 pm

Plus visual approach using the auto-throttle. And only 15 degrees of flap when it finished up.

Data may now be available from the Cockpit Voice Recorder - not published yet though.
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RE: Indonesian B737 Crash, Part 3

Sun Mar 18, 2007 7:21 pm

Has it already been confirmed the A/T was in operation throughout the sequence? I have been under the impression that was an assumption we all made in order to explore the possibilites associated with such an action.
 
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RE: Indonesian B737 Crash, Part 3

Sun Mar 18, 2007 7:47 pm

A high energy approach was conducted in visual conditions in calm wind. (As reported by many witnesses, some industry, some pax) The ILS (which has a 2 degree lateral offset) was probably being used for track/glide slope reference. A/T use in visual approaches is GA SOP, so its not unlikely.
Credible witnesses report aircraft touchdown 695 meters deep on 2200 meter runway. One bounce of approximately 200 meters, followed by two more bounces of lesser magnitude. Reverser deployment and speedbrake extension reported during the bounce sequence. Third bounce was nose down with vertical velocity to cause nose tyres to fail. Rubber deposits on runway look consistent with heavy braking.

Post crash pictures indicate flap position on both wings 15 degrees. Normal landing flap either 30 or 40.

All evidence so far points to the crew, for whatever reason, attempting a landing from a rushed, hot/high approach with insufficient flap. Reverser selection immediately after touchdown might have prevented a baulked landing/go around attempt due to 737 procedural warning prohibiting go around after reversers unlocked.

Possibly one reverser was inop preflight, as yet unverified.

Windshear was reported early as a possible factor, this has since been discounted.

Cur...
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RE: Indonesian B737 Crash, Part 3

Sun Mar 18, 2007 8:20 pm

Quoting Curmudgeon (Reply 6):
Third bounce was nose down with vertical velocity to cause nose tyres to fail.

Couple of queries, Curmudgeon. The only 'graphical reconstruction' I've seen showed the nosewheels going on the first bounce - was it definitely not until the third one? In addition, I've previously understood that the nosewheels themselves broke off, it wasn't just the tyres going?
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baroque
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RE: Indonesian B737 Crash, Part 3

Sun Mar 18, 2007 10:06 pm

Quoting NAV20 (Reply 4):
And only 15 degrees of flap when it finished up.

But sequence of flap settings unknown at this time to this thread.
 
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 12:16 am

Quoting Baroque (Reply 8):
But sequence of flap settings unknown at this time to this thread.

Although FDR data reported to indicate that flaps were not in "normal landing config" during the approach.
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mandala499
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 1:54 am

Cur et al,
Just been updated on the SOP, though not yet clear... GA SOP is A/T on during visual down to 400' AGL, stable by 500' AGL still in force. But, some do continue on a/t to landing, but manually cut off A/T (normally at about 100' AGL)and it is said by 1 GA pilot that "we do not rely on the A/T cutting out at 27' on visuals".

Based on the ATC transcripts and distances reported, though its accuracy cannot be used any further than a "what we have at the moment", I see no indications there that the whole approach was done faster than normal.

At 30NM @ 9000ft on the first position relay by ATC, it happened at 10 mins before the crash, by the calculations, that surmounts to an average groundspeed from that point to the runway of 180Kts GND SPD. This however, is not very useful...

The position relays to traffic that GA200 was at 10NM, 9NM and 7NM were also calculated, and it appears the average groundspeed between those positions and the time of the crash, are about 140kt each... though that may sound slow for a flap15, bear in mind the inaccuracies of these calculations.

However, the consistency of it, can lead to indicating that, there was a possibility that the approach was stable until the final phases of the approach... where we then start relying on the witnesses.

Now, it seems that the unstable approach comes late in the final, based on the recent eyewitness recollection I took yesterday. Something made them high on the short finals.

Now IF IT IS a flap15...

A flap15 landing at heavy landing weights will result in a higher nose attitude on final, the temptation is to put the nose down to have a quick better look... net result, speed builds up, and the way to return to the speed, is pull the nose up again and reduce the thrust a bit. Now, there is a tendency for this cycle to repeat again and again, and if one isn't careful, you'd end up high anyways. Now, it is unclear whether this happened or not and if so, when it happened, but this is a possibility on how they could end up high.

As to fast, it is only said so far that they're "faster than normal"... unclear if this is faster than a normal flap30 landing, or even faster than a flap15 landing.

As for the floating flare, the flap 15 itself can explain for a lot, with runway quickly passing you, you either go around or put it down... put it down wrongly, and you'd bounce.

it would appear that they have "at least" 3 distinct chances to execute the missed approach...
1. When they had the flap problem. Possible reason, enough distance to go, plus potential traffic conflict with the departing MD80 turning towards them, (as the Missed Approach procedure ILS and the visual traffic pattern for jets (left pattern for 09) could put them into conflict. Training flight wasn't a factor at this time.
2. Short finals, possibly they didn't go around due to the proximity to the training flight that had just taken off.
3. After first bounce, again, the above, but not much else.

Now, though in my opinion they should have taken the go-around, the above MAY explain why they didn't... but it's not up to me to decide whether ultimately their decision was right or wrong.

Now, one more thing on the flap mystery. MANY witnesses stated they saw the flap vortex condensation (whatever it's called)... on the ground and in the aircraft. Now, would it happen to a flap15 (in the tropics, at say Temp: 25 Dew: 24)?

mandala499

[Edited 2007-03-18 19:01:28]
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 2:30 am

I think someone asked about the brakes...

http://www.thejakartapost.com/yesterdaydetail.asp?fileid=20070310.@01
Capt. Novianto, vice president of Garuda's flight safety department, said Yogyakarta's runway is uneven in some places.

"We feel the wavy points when taxiing after landing and when taking off," said Novianto, a senior pilot experienced in flying Boeing 737-400 aircraft. Garuda has 39 of them.

He added that the aircraft's braking system was malfunctioning upon landing at Jakarta's Soekarno-Hatta airport from Palembang on Tuesday, a day before the crash.

"The damage was repaired on Tuesday night and the plane was declared flight-worthy afterward," he told The Jakarta Post.


That was published in the Jakarta Post on 10th...

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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 7:25 am

Rough runways cause uneven braking, and can cause oscillation on the brake pedals. I have some experience in the certification test world, and can say that it was a big deal to find the smoothest surface possible for testing. Anytime the aircraft sees vertical acceleration the brake effectiveness is momentarily degraded because the aircraft is, for that instant, not supplying down force to the wheels.

The oscillation thing is caused when the frequency of the bumps starts a vibration in the foot/pedal couple. The pedals are sprung to allow normal brake action, and when your feet start to get out of sync with the bumps the braking action is also reduced. The only cure is to remove pressure from the pedals and then try again.

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NAV20
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 8:49 am

Quoting Mandala499 (Reply 10):
net result, speed builds up, and the way to return to the speed, is pull the nose up again and reduce the thrust a bit. Now, there is a tendency for this cycle to repeat again and again, and if one isn't careful, you'd end up high anyways.

We're thinking very much along the same lines, Mandala499 - as I said on the previous thread, "A bit too fast, a bit too high, reactions a bit too late - and suddenly there were 'no good options.'

In my view it is entirely possible that that the situation 'crept up' on the pilots. The reason that they didn't put down more flap in good time may well have been the simplest one of all - that they were above 'placard speed' for 30 degrees (which, at a guess, and subject to Curmudgeon's view, is maybe about 175 knots)?

The solution, as you say, would be to cut power and raise the nose - but it's possible that before that took effect in terms of reduced speed, the runway began looking uncomfortably close and also pretty short, 'instinct' took over, and down went the nose again. And, as you say, they may not have been able even to SEE the runway over the panel a lot of the time.

Easy to write that, as a sort of criticism of them, from my livingroom. But it's worth remembering that, given that 175 knots is almost 3 miles per minute, they probably had less than 60 seconds to sort things out, or alternatively to decide to go around. It certainly illlustrates how RIGHT alriline pilots have to get it, all day, every day, on every flight........

I hope that, if the CVR data has in fact been downloaded now, you hear something about its contents from your contacts soon. Any details of how experienced that First Officer is would also be interesting.
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jetfuel
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 10:58 am

Quoting Curmudgeon (Reply 6):
One bounce of approximately 200 meters,



Quoting NAV20 (Reply 13):
they probably had less than 60 seconds to sort things out, or alternatively to decide to go around

If only...
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mandala499
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 12:39 pm

NAV,
Watch it mate, you're bordering on careless talk again IMO.
No, with Garuda, if you cannot deploy in time, you abandon the approach. I disagree that the speed has been allowed to stay high leading to the flaps being prevented from deploying... Why?
Please bear in mind those calculated groundspeeds...
Please bear in mind Garuda's SOP that's etched in their brain (for normal operations anyways)... Garuda tends to dangle the dunlops and slap those flaps quite far out on the approach...

It is more likely that the flaps did not deploy due to a malfunction.

1. If you slap those flap levers, they are going to deploy no matter if you're faster. If you are too fast, they'll just rip off. Malfunctions can happen when the strains are too much, and most likely due to assymetry protections.

2. If they were unable to deploy flaps due to speed, after the MD80 has passed, and before they get tooo low, they can go-around. There's nothing wrong in deliberately overshooting the approach when executing a missed approach and traffic avoidance... that is... if nothing is wrong.

Now, WITHOUT any problems, pilots do tend to come in high into JOG thanks to the terrain... visual illusions due to runway shape upon approach... THR above preceeding terrain (and no overrun that side), upslope on the TDZ, then downslope onto the last 500ft of the runway...

You really do not want to come in too low when landing at JOG, you might shear your landing gear on the river embankment just before the threshold...

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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 2:13 pm

Quoting Mandala499 (Reply 15):
No, with Garuda, if you cannot deploy in time, you abandon the approach.

I agree that why they chose not to abort is a question that has to be answered, Mandala.

But we now have a comment from the chief investigator (in that article I linked to, link re-posted below) that the flaps did not deploy. He doesn't say why - except that he says that possibly 'high speed' was the cause.

"The chief crash investigator, Mardjono Siswosuwarno, said the aircraft's wing flaps failed to extend for landing and that might have been caused by the high speed."

Quoting Mandala499 (Reply 15):
Please bear in mind those calculated groundspeeds...

The chief investigator also said, without equivocation, that the approach speed was higher than normal. Since he'll undoubtedly have data from the Flight Data Recorder (and possibly the Cockpit Voice Recorder as well, by now) I think we have to take an element of overspeed as an established fact, not a mere possibility. Agreed, we still don't know how MUCH overspeed.

“This could be a contributing factor, but what is more important is that the plane's speed was higher than normal. Why? We don't know yet,” Mr Siswosuwarno, from the National Transport Safety Commission, said."

http://www.news.com.au/heraldsun/story/0,,21400951-5005961,00.html

Quoting Mandala499 (Reply 15):
Please bear in mind Garuda's SOP that's etched in their brain

I'm sure that, if it turns out that the pilots departed from this (or any other) airline's SOP, this won't be the first or the last time that happens. As to 'etched in the brain,' that's why I hope we learn some time soon how many hours that First Officer (PF) had in his logbook.
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mandala499
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 4:40 pm

No... I disagree for him to say the high speed as the cause, unless there are other information available (FDR). Bear in minds those comments are not based on official reports, therefore one must be careful with the details.

Speed was higher than normal, but, a flap15 landing would be faster than normal. Now the problem is, he (and you) seem to imply that the overspeed prevented the flap deployment.

However, another article, http://www.smh.com.au/news/world/win...-jet/2007/03/16/1173722744310.html
or this one's a bit more complete...
http://www.theage.com.au/news/nation...aims/2007/03/16/1173722750242.html

I had called the authors who made those articles, and it is said specifically that the investigators said the lack of flaps may have caused the aircraft to go in faster.

I am sticking on the speed due to lack of flaps, not the lack of flaps due to speed. because Currently publicly available information do not support the latter, neither do the SOPs of the crew.

I have talked to engineers and also engineers with accident investigation training, and crew that, unless you've grossly exceeded the speeds, the flaps would not extend any further because of the strains, however, overspeeding in an approach should not cause the flaps to malfunction other than an assymetry lockout due to the forces involved. Other than that, it's either flap deploying, or flaps ripping off.

I really do not understand why that you seem to be presuming (sorry if I'm wrong on this) that it was a very fast descent and they can't slow down in time? I don't buy that FOR THE MOMENT.

Here is some data:
30NM from the airport aircraft position was at 9000ft. This is again, normal, nothing out of the ordinary. That was also, 10 mins before the aircraft went to the runway and that was with a HUGE allowance of a 1 minute time (well, 50 secs) on runway before it crashed! The allowance was put in to put already put a faster speed bias and cushion out any timing errors on the transcripts.
Do some calculations, the average speed between that position and the runway was 180Knots.

At 10 miles, it was visual and 4 mins before going to the runway... that gives 150Knots
At 9 miles, it was visual and still about 4 mins before going to the runway... that gives 145knots.
At 7 miles, it was visual and about 3 mins from the runway... that gives 140knots!

The flap limit speeds are:
1 - 230KIAS, 2 - 230KIAS, 5 - 225KIAS, 10 - 210KIAS, 15 - 195KIAS, 25 - 190KIAS, 30 - 180KIAS, 40 - 158KIAS

Those are speeds where if you deploy positions above those speeds, you're asking for the flaps to jam, not rip off yet.

Now, it seems utterly illogical at the current available information that the planes flaps would not deploy because the airplanes were going too fast. If from 30 miles, the average speed to go was 180Knots, the more time it spends above that speed during that period MUST also lead to more time it spends below that speed. Now, you can deploy flap30 at 180 knots (groundspeed vs wind not withstanding).

Vref15 at:
70 tons = 177kias, 65 tons = 171 knots, 60 tons = 164 knots, 55 tons = 156 knots, 50 tons = 149 knots.
If stall speeds are Vref/1.3, those speed numbers based on position relays, still make sense. However, for the final speed being say 180KIAS, doesn't make sense with the relays.

This is why I think it is unlikely that the flaps would jam or were not extended "because they were coming in too fast", but more likely that the speeds were fast because they were not able to deploy landing flaps.

It's a minor difference in arranging the sentence, but its implications are huge Nav... what is implied in flaps not extending because they could not slow down enough would even surprise the cowboy gung-ho pilots, why? Coz they remember they have 1 tool... the speedbrake! Although Boeing doesn't recommend the use of speedbrakes above flap5, it can be done when you've screwed up your descent planning and you need to get in that slot quickly... For them, deploying landing flaps is more important than not deploying... because the implications are too obvious.

mandala499
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jetfuel
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 4:52 pm

At 7 miles, it was visual and about 3 mins from the runway

Do we know the altitude? That would give us the approach profile. - with various flaps
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 6:54 pm

Any Trascripts of the CVR Available publically yet.
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 7:40 pm

As a result from this crash and some other crashes recently, the Ministry of Transportation has decided to introduce 3 rating categories to all carriers in Indonesia:

Rating 1: Comply to all procedures
Rating 2: Not fully comply but manageable
Rating 3: Not comply to most procedures and difficult to be 'cure'

Based on the news on SCTV at 6 pm just now, it was reported that there were 3 carriers in Rating 3 and the license of 1 of them is expected to be suspended very very soon. Most speculated that AdamAir will be the one.

I am just wondering why the government doesn't suspend all 3 carriers in Rating 3. The other 2 are no less dangerous than the intended 1.

In the news as well, it was reported that a Lion Air's MD80 failed to take off at Banjarmasin today due to an 'indicator' not functioning.  no 
 
NAV20
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 7:42 pm

Hi MEL - no, no information yet. We may never see a full transcript, they're not often published. Anyway, there has only been the one story about the data being recovered so far, the journalist may have misheard.

Quoting Mandala499 (Reply 17):
Now the problem is, he (and you) seem to imply that the overspeed prevented the flap deployment.

Much relieved, Mandala, I think I see where the misunderstanding is now.

We're taking a bit of an 'opposite view' on flaps. It's not normally a question of workng out the highest speed at which you dare lower them. In a properly-executed approach, you keep the rate of descent fairly shallow, without too much power on, and as the aeroplane decelerates 'naturally,' through drag, you lower the flaps in stages at given speeds. These will normally be far lower than the 'danger levels' you quote.

However, if you approach on a too-steep descent path, for whatever reason, the dive itself may keep the speed above your 'target' lowering level, however much you slack off the power. The normal remedy for that is to ease the nose up to bleed off speed until you can lower more flap. But, of course, keep that up for too long and you'll find yourself well above the proper glideslope, and at risk of overshooting.

That was all I was suggesting, as a possibility; that the pilot found himself 'between two stools,' needing to keep the nose up to get down to his target speed for 30 degrees of flap, but feeling impelled to push it down for fear of coming in too high. And that he maybe ended up with the worst of both worlds, not enough flap down AND too high anyway.

In any event, I'm sure that we can both agree that there was a remedy immediately to hand; a go-around. So there is no way that not having enough flap down, for WHATEVER reason, could or should have caused this accident.

[Edited 2007-03-19 12:48:47]
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Curmudgeon
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 8:10 pm

1. Trying to parse the time/distance equation is useless if using whole minutes. At those ranges you need to know the time in seconds. That still gives you groundspeed, and if you know the wind on the approach, you can deduce airspeed.

2. Speed at ten miles is not a predictor of speed at 0.1 mile.

3. Flaps don't rip off for over speeds in the 20-30% range. I know of at least two incidents where flaps 30 was set at 205-210 kts without damage, and one where flaps one was discovered at 320 kts. (I wonder what he's doing now?)

4. The 737 does not bleed energy well, as I have noted a few times now. A high energy approach can be the result of being too high (potential energy) or too fast (kinetic energy) or a combination of both. In any event the speedbrakes and wheel brakes and reversers can dissipate a finite amount of energy in the time/distance available. If much of that distance is squandered floating and bouncing it becomes an impossible task.

5. The flap placard speeds noted above do not correspond to the 737-400 series aircraft that I have flown, but I'm too tired to drag out a manual. 250 for 1 to 5, 215 for 10, 205 for 15 ,195 for 15 ,185 for 25, 175 for 30 ,162 for 40 from memory. Please remember that these are placard speeds, so they aren't something that I commit to reliable memory.

6. As I noted previously the difference between flaps 15 approach speeds and flaps 30 is approximately 10 (ten) knots.

7. Vref is the minimum approach speed. While it is 1.3 Vs for configuration, pilots that aren't finished living yet fly Vref + 5 minimum. Below Vref the drag increases rapidly as does fuel flow required for flight. Vref is the trade-off speed that balances total energy against the higher risk of a stall or high descent rates close to the ground.

Cur...
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NAV20
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 9:11 pm

Quoting 9MMAR (Reply 20):
As a result from this crash and some other crashes recently, the Ministry of Transportation has decided to introduce 3 rating categories to all carriers in Indonesia:

Rating 1: Comply to all procedures

Thanks, 9MMAR, new information.

Any indication of what those 'procedures' entail? Is it just maintenance, or does it cover things like scheduling, pilot selection/training as well?
"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci
 
mandala499
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 9:14 pm

Aha... No wonder...

Well, 30NM at 9000ft is normal anyways. Nothing seems special.
It isn't a good method to use the transcripts to measure speed of the aircraft, but, it does give an idea on how things were flowing, and in this case, I see nothing that hints at them being rushed.

Quote:
However, if you approach on a too-steep descent path, for whatever reason, the dive itself may keep the speed above your 'target' lowering level, however much you slack off the power. The normal remedy for that is to ease the nose up to bleed off speed until you can lower more flap. But, of course, keep that up for too long and you'll find yourself well above the proper glideslope, and at risk of overshooting.

Nav, are you saying it's too steep descent path prior to flap and gear deployment, or after? If the former, I still doubt your possibility, I still find it more likely that things went wrong after they started deploying the flaps and then landing gear... it is the oscillation AFTER the decided to continue on flap15-ish that they ended up being above slope and/or faster...

Approaching 09 in the morning, directly into the sun, flap stuck at somewhere, somehow decided to continue, nose high approach... nice glare huh? Plus the visual tricks on the slope, many pilots come in slightly higher than they should when on visuals (and disregarding the PAPIs)... the threshold is above the immediately preceeding terrain, slopes up to the end of the TDZ, then down until the last 300' on the other end (when standing at 27, you can't see the 737's tail at 09!)

I find these a more likely cause of them ending up too high and fast rather than the rushed and can't slow down to deploy flaps method.

Cur,
The 737 don't like slowing down much, that's why the cowboy bunch of them know the rules of thumb and are not unwilling to use the speedbrakes... Now with Garuda, it's "keep it neat but the speedbrake's there too if you need it".

And yes, those placard speeds I got are weird! Yours sound more correct, probably the ones I got are "company mods". Oh hang on, Bugga! They're 733/5 placards from another operator! *bangs head on table*

Mandala499
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NAV20
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RE: Indonesian B737 Crash, Part 3

Mon Mar 19, 2007 9:41 pm

Quoting Mandala499 (Reply 24):
Nav, are you saying it's too steep descent path prior to flap and gear deployment, or after?

I'm saying that the whole approach, from starting the descent, should have been coordinated. Gear, speeds, flap settings, direction, glidepath, everything. That aeroplane should have been completely balanced and trimmed and in full landing configuration, speed, flaps, and all, about 3 miles from touchdown.

Had that been done, any problem with the flaps would have been noted at that point - and the pilots would have had plenty of time to decide on their response. That could have ranged from a modified approach (preferably including a 'Pan - aircraft in difficulties' call to the tower) to a go-around.

I'm struck by the fact that the phrase 'in the last few seconds before landing' has been repeated in several of the articles relating to the flaps problem. Putting down more flap a few seconds before landing - or even trying to - would be pilot error by any standards. It wouldn't slow the aeroplane down significantly - all it would do is generate a helluva lot more lift, which is the LAST thing you'd need or want just before landing.
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md80fanatic
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RE: Indonesian B737 Crash, Part 3

Tue Mar 20, 2007 1:39 am

I've been away for a few days.....has there been any new information released? Any news of the CVR?
 
jetfuel
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RE: Indonesian B737 Crash, Part 3

Tue Mar 20, 2007 2:26 am

experts in the United States had repaired the cockpit voice recorder, which was badly burnt in the fire, so investigators can download the last 30 minutes of the crew's conversations
http://www.news.com.au/heraldsun/story/0,21985,21403188-661,00.html
Thats all so far
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RE: Indonesian B737 Crash, Part 3

Tue Mar 20, 2007 2:50 am

.
.
.
Thanks JetFuel.  Smile
 
mandala499
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RE: Indonesian B737 Crash, Part 3

Tue Mar 20, 2007 9:32 am

NAV,
There is so far, no evidence that the whole descent was botched. Garuda would like to be stable way more than 3 miles before landing, they like to be in landing config from further than most people! Now the ATC transcripts reveal the aircraft was at 9000ft 30NM from the airport, at 10mins to touchdown, which indicates that everything was normal.

The word "in the last few seconds before landing" is not what the investigators said, it is what the journalists said. I wouldn't get bogged down by those words if I were you.

Mandala499
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NAV20
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RE: Indonesian B737 Crash, Part 3

Tue Mar 20, 2007 10:19 am

Quoting Mandala499 (Reply 15):
No, with Garuda, if you cannot deploy in time, you abandon the approach.



Quoting Mandala499 (Reply 15):
Please bear in mind Garuda's SOP that's etched in their brain



Quoting Mandala499 (Reply 29):
Garuda would like to be stable way more than 3 miles before landing, they like to be in landing config from further than most people!

Mandala499, you seem to have more faith in Garuda than I have in Qantas (which is saying something)! In the wrong combination of circumstances, ANY airline can have an accident.

In any case, I would hope that Garuda is already revisiting and scrutinising ALL their procedures, just on the basis of what we know already. The logic is simple:-

1. If 'pilot error' turns out to be the main cause, they have to look at pilot selection and training.

2. If it turns out to be 'mechanical malfunction,' they need to run the magnifying glass over maintenance and inspection.

In practice, I hope that they are already doing both.

Breaking the 'flaps 15/30' thing down in a similar way:-

1. If the pilots had followed normal procedure, they'd have reduced to landing speed and selected 30 degrees of flap some distance out.

2. Had the flaps malfunctioned (i.e. failed to deploy) at that time, they'd have had plenty of time to follow correct procedures and still land safely.

3, Therefore, if the pilots are claiming that a flap malfunction (failure to deploy) caused the accident, there are only two possibilities:-

EITHER they selected the additional flap so late in the approach that they did not have time to react to it failing to deploy (pilot error) -

OR the malfunction took a hitherto unheard-of form; that is, the flaps initially deployed and then, by some miraculous combination of circumstances, retracted THEMSELVES at the last moment.

Hope all that makes my views (and the logic I am applying) clearer.

[Edited 2007-03-20 03:25:44]
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mandala499
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RE: Indonesian B737 Crash, Part 3

Tue Mar 20, 2007 8:44 pm

Nav,
I seriously doubt that they had this accident because they went in too fast and cannot deploy their flaps in time, assuming the flaps were all working.

Whether this is pilot error or mechanical failure? It's possible that it's both. However, some are saying it's pilot error leading to mechanical failure (flaps not extending due to speed), and I tend to take that as a rare possibility, and it is more likely that it was mechanical malfunction leading to pilot error.

I'd like to raise another write off that happened on 24th Dec here in Indonesia, also involving a 734. According to NTSB Factual Report (id: DCA07WA017):

Quote:
On December 24, 2006, at around 0050 UTC, a Boeing 737-400, registration PK-LIJ, operated by Lion Air departed runway 31 at Hasanuddin Airport, Makassar, Sulawesi, Indonesia. The flight was a scheduled domestic passenger flight from Jakarta carrying 157 passengers, 2 flight crew and 5 flight attendants. On arrival, the aircraft was executing a visual approach via a left downwind pattern to runway 31. The crew maneuvered in a close pattern due to proximity of terrain on under the base and final approach areas of runway 31. The weather was reported to be 10 km visibility (approximately 6 sm), surface wind calm, no clouds, and surface temperature 29 C. According to a written report from the crew, when they selected the flaps from 15 deg. to 30 deg. on final, they observed that the flaps indicator indicated a asymmetrical condition. According to the report, the crew re-selected the flaps back to 15 deg. and they elected to continue approach and landing. The report said that the crew referred to the QRH for the situation and they also checked the actual landing distance for flaps 15 deg. landing configuration. The captain was the pilot flying. According to ground witness reports, on landing the aircraft was not on centerline, it bounced twice, and swerved down the runway. The aircraft came to rest beyond the runway in the overrun area. The passengers were evacuated with no reports of injuries. According to a report from the local airport authority, the aircraft sustained substantial damage; the right main landing gear was detached, the left main gear protruded through the left wing structure, and some fuselage skin was wrinkled. There was a significant ground scar on the runway surface. The FDR and CVR has been removed and secured after the event.

In this case, again, no emergency was transmitted, no malfunction were mentioned to the ATC, and the reports of "amazing speed" was noted...

It seems more like the case of a long visual final, early deployment to flap15, then the same thing as what happened to LIJ happened.

Now in the case of GA200, they were landing at runway 09, at 7am, straight into the low sun, at a higher than normal nose attitude (glare probably adds to the difficulty). At a runway where the threshold is higher than the preceeding terrain, and where the runway perimeter is only 25m from the threshold, preceeded by an elevated riverbank. The TDZ 09 itself is an upslope, but it goes downhill down to the last 100m of the runway at the end of 27, where it levels out. (Just for an idea, standing at 27, you won't be able to see the tail of a 737 at 09). Even under normal landing config, flights coming in tend to touchdown late. Colleagues flying to JOG said being low there is a bit risky, there's also a flyover on finals.

It's all sounding like "pilot error precipitated by the flap lockout"...

Mandala499

[Edited 2007-03-20 13:55:34]
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Buyantukhaa
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RE: Indonesian B737 Crash, Part 3

Tue Mar 20, 2007 9:39 pm

Quoting Mandala499 (Reply 31):
I'd like to raise another write off that happened on 24th Dec here in Indonesia, also involving a 734.

Mandala, that's a very interesting fact... It does sound like something very similar could have happened here.The similarities are striking!
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nwafflyer
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RE: Indonesian B737 Crash, Part 3

Wed Mar 21, 2007 7:12 am

Off topic to be sure, but other than posting, how do I add this to my 'starred topics?'

I have nothing to add to what the experts have already said, but I am very interested in following this
 
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Buyantukhaa
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RE: Indonesian B737 Crash, Part 3

Wed Mar 21, 2007 8:30 am

Quoting Nwafflyer (Reply 33):
how do I add this to my 'starred topics?'

In http://www.airliners.net/discussions/general_aviation/ just click on the star of the thread.

Or click on the star above (at the thread starter.)
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NAV20
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RE: Indonesian B737 Crash, Part 3

Wed Mar 21, 2007 8:40 am

NWafflyer, on the main Civ. Av. page, click on the star to the left of the thread title. Star should turn yellow and the thread will be easy to find from then on.

Mandala499, that Lion Air incident last December seems to be a carbon copy of this one, except that, thankfully, no-one got killed or hurt. Please note, though, that that is merely a factual report, which says (among other things) that the pilots 'reported' a flap malfunction. As with GA200, investigations are 'still in progress' and no formal report has been issued on the cause of that incident. In particular, no-one knows yet, in either case, whether the FDR and CVR confirm the pilots' accounts.

Quoting Mandala499 (Reply 31):
Now in the case of GA200, they were landing at runway 09, at 7am, straight into the low sun, at a higher than normal nose attitude (glare probably adds to the difficulty). At a runway where the threshold is higher than the preceeding terrain, and where the runway perimeter is only 25m from the threshold, preceeded by an elevated riverbank.

Maybe another misunderstanding here - no-one is saying, certainly not me, that landing with less than recommended flap isn't more difficult than landing in normal configuration. We need Curmudgeon to tell us what it's like in a 737 - I would expect that, as with other aeroplanes, it results in a higher landing speed, the need to maintain an increased angle of attack (i.e. keep the nose higher in the flare), and a more restricted forward view.

There's an underlying risk in that - the higher angle, plus the extra speed, makes the aeroplane MORE LIKELY to bounce unless you make sure that the touchdown is as smooth as you can make it. But all pilots are (or should be) trained to land with reduced flap, and should be ready for that problem and able to deal with it.

Quoting Mandala499 (Reply 31):
It's all sounding like "pilot error precipitated by the flap lockout"...

Happy to agree with that in the sense that any flap malfunction won't have helped. But, as explained above, flap problems shouldn't cause accidents if procedures are correct and the pilot has adequate skill. The crucial question (in BOTH incidents) is WHEN the pilots selected the lower flap setting. In that connection, please note from that 'factual report' that Lion Air also carried out a visual apporach and "The crew maneuvered in a close pattern due to proximity of terrain on under the base and final approach areas of runway 31." Once again suggests that selection of landing flap may have been closer in than it should have been?
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mandala499
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RE: Indonesian B737 Crash, Part 3

Wed Mar 21, 2007 8:28 pm

NAV,
In the case of -LIJ, that report did not mention the crew notifying the ATC of the flap problem at anytime during the flight. This is consistent with all the info received on that flight over here... unless I missed something. Although the report isn't out, sources within Lion have said that flap assymetry caused the lockout.

As to a flap15 landing, well, it is "not the usual" unless one practices them often... a higher angle of attack is needed, but I've been told by few who had done flap15 due to malfunctions that the flare requires less of a nose up... (ground effect, etc...)... yes, perhaps Cur would be able to tell us here.

Quote:
makes the aeroplane MORE LIKELY to bounce unless you make sure that the touchdown is as smooth as you can make it.

One case brought to me was one where the pilot had to manipulate the speedbrakes to bring the airplane down... I guess there are just a lot of variables involved here.

What is deemed "Adequate skills" may differ from place to place, it seems that my region has the unfortunate lack in experience on flap15 landings... but that doesn't necessarily mean that the skills here are inadequate unless overall, there is a deficiency.

As to approaching Makassar 31, the tight pattern is required regardless due to the terrain. That does not mean whatever flap deployment one does there is late, and I don't see anything indicating a late flap deployment in the case of LIJ either.

The comment "The crew maneuvered in a close pattern due to proximity of terrain on under the base and final approach areas of runway 31." has nothing to do with early/late flap deployment and neither does it imply so. It's flap15 gear down by the time you're abeam of the runway, and flap30 anywhere from downwind to base leg as long as you're more than 500' AGL. I've been in approaches where flap30 was deployed abeam of the runway... coz yes, it's pretty tight over there! And it was a flap40 landing.

Late, in terms of flap deployment, is only when you haven't been in landing config by the time you've passed 500' AGL in visual (stable & in the slot not withstanding).

The question is always WHEN they deployed the landing flap, but again...

Quote:
Once again suggests that selection of landing flap may have been closer in than it should have been?

Indicates your desire to want to hear "yes, they deployed it late!"...

Quote:
EITHER they selected the additional flap so late in the approach that they did not have time to react to it failing to deploy (pilot error) -

OR the malfunction took a hitherto unheard-of form; that is, the flaps initially deployed and then, by some miraculous combination of circumstances, retracted THEMSELVES at the last moment.

And there again... your view was they were late, or something which if it does end up being reported as a cause in the investigations, would make me wonder what the investigators have been smoking or what Boeing was smoking when they designed it.

Is it just not possible, in your view, that this could have happened if the flaps were deployed according to the normal schedule at the correct phase in time, at the correct approach profile prior to deploying flap30, but then something just screws up? Or the pilots just simply screwed up as a result, call it inadequate skill or whatever else?

It seems that the approaches we're taking on this accident is totally opposite. One being from no deviation from normal procedures and investigating progressive deviations until the possible results matches what happened, the other being from a total deviation and trying to find ways to explain what happened...

Mandala499
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NAV20
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RE: Indonesian B737 Crash, Part 3

Wed Mar 21, 2007 9:27 pm

Getting a bit convoluted, Mandala499 - but this is a great thread, we're both still polite!  Smile

Quoting Mandala499 (Reply 36):
Is it just not possible, in your view, that this could have happened if the flaps were deployed according to the normal schedule at the correct phase in time, at the correct approach profile prior to deploying flap30, but then something just screws up?

Look - anything's 'possible.' But yes, basically I'm saying that if flaps 30 was selected at the proper time, with the aeroplane at the correct speed, on the glideslope etc., any malfunction (which would almost certainly have been asymmetric) need not have caused the accident; because the pilots would have had plenty of time either to adjust the approach or to execute a go-around.

Quoting Mandala499 (Reply 36):
but then something just screws up?

If you mean a mechanical problem, that would have had to be something additional, something different.

Quoting Mandala499 (Reply 36):
As to a flap15 landing, well, it is "not the usual" unless one practices them often... a higher angle of attack is needed, but I've been told by few who had done flap15 due to malfunctions that the flare requires less of a nose up...

That's interesting; because I can assure you that pilot training - even for the likes of me, who only got to PPL standard - normally DOES include learning about, and practising, landing with malfunctioning flaps. Even, in my case (and admittedly only in a Cessna) landing with no flaps at all. The way you phrased that suggests that the only pilots you've met lately who can tell you about dealing with that sort of situation are a 'few who had done flap15 due to malfunctions.'

I would hope that the Training Captains of the world's airlines (not just Garuda or Lion Air) have noted that there have been two accidents in less than three months, both possibly involving the pilots not being able to deal with flap malfunctions, and have already changed their training programmes to suit.

That's the real point of investigating (and even discussing) past accidents; to learn lessons from them in order, if possible, to prevent the same thing happening again.
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baroque
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RE: Indonesian B737 Crash, Part 3

Wed Mar 21, 2007 9:30 pm

Hmmm. Are we even sure of the state of flaps when the plane came to a halt, let alone their position during the "landing". Still less do we know in what setting the pilots thought they were in or what they had been trying to do. If we do know that I will be a bit apologetic, only a bit because there has been so much surmise, that the facts (few as they are) have tended to get lost in the general mist.

We do know courtesy of Cur that 737s tend to float, so presumably that would add to whatever woes were generated by other events.

Above all, we do need to be patient. Whatever the findings are, they are going to be very serious for a number of parties. It is extremely important that they are right. It would not be possible to have a go around for the findings.

Difficult times for all the good folk at Garuda - and there are many.
 
mandala499
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RE: Indonesian B737 Crash, Part 3

Wed Mar 21, 2007 10:25 pm

Well Nav,
Though it can get strenuous at times, but then, the politeness is greatly appreciated... way better than endless mudslinging. One thing I agree on is, there needs to be a look on how pilots deal with these situations, and yes, perhaps the flap malfunction procedures need to be reviewed... at least on getting more emphasis on handling of the situation.

There have been great inputs by pilots regarding a flap15 situation both by those who have experienced such situation, and those who haven't... with equally disturbing split in views over here about how that accident should have been handled, but at least this raises awareness of potential conflicts in doctrine and airmanship that needs to be addressed... in both accidents, the pilots have followed the procedures (according to the initial reports), which if proven correct, and these kinds of accidents still happen, yes, training, manuals, etc. definitely needs another look at.

Btw, thanks for the explanation on the Cessna thing, now I understand how you came to your viewpoint...

Now, let's hope that we get a full accident investigation report...

Mandala499
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tetuko
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RE: Indonesian B737 Crash, Part 3

Wed Mar 21, 2007 11:21 pm

Hi, I'm new here.
If there's a problem with the flaps (either assymetrical deployment or stuck flaps at a certain degrees), shouldn't the pilot feels something from the aircraft behaviour?

And by they way...
Hi Ger.
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NAV20
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RE: Indonesian B737 Crash, Part 3

Wed Mar 21, 2007 11:28 pm

Glad things are clearer, Mnadala.  Smile

Found this earler - a very full report on a mucked-up approach in 2000 by an 11,000-hour pilot. Not in Indonesia, but in 'Beautiful Downtown Burbank,' Calif., USA.

Several contributing causes, like ATC telling him to fly fast as he lined up, the airline modifying the autobrake, etc. But the essential cause of the accident was that, finding himself too fast and too high, instead of going around, he tried to go through with the landing. He finished up approaching at over 180 knots and a descent rate of 2,600 feet per minute (which I believe is about four times the normal rate).

I can't quote extracts from the report because it's copy-protected - you'll have to read all 8 pages! But I've copied out this bit because you have to admire the pilot for admitting what went wrong, and being completely honest about how he felt, and why he finished up crash-landing:-

“He stated that the airport looked normal from 500 feet but that he was not ‘in the slot’ because his airspeed was too high, the report stated. “He indicated that he became ‘fixated on the runway,’ and he could not explain why he did not perform a go-around maneuver.”

http://208.37.5.10/ap/ap_july03.pdf
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baroque
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RE: Indonesian B737 Crash, Part 3

Thu Mar 22, 2007 12:54 am

Quoting Tetuko (Reply 40):
Hi, I'm new here.
If there's a problem with the flaps (either assymetrical deployment or stuck flaps at a certain degrees), shouldn't the pilot feels something from the aircraft behaviour?

Selamat datang. As best I can work it out, Tetuko, there might (or might not) have been a problem with the flaps, which the pilots might or might not have detected and they might or might not have reacted appropriately. But there are much wiser than I in this thread. Whatever else, it came in high and fast and bounced.
 
mandala499
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RE: Indonesian B737 Crash, Part 3

Thu Mar 22, 2007 1:38 pm

Tetuko,
Should the pilot feel it? Of course, but as to feel the assymetry, not always. Besides, an assymmetry detection error is a possibility that needs to be looked at. *I forgot who raised that and where*

NAV,
As to the WN Burbank accident, the difference is as you said, the ATC... in the case of GZC and LIJ, that wasn't the case.

New rumours now surfacing here that the airplane came at 205kts at flap5... which is something I don't agree with given the flaps he aircraft ended up with.

Quote:
“He stated that the airport looked normal from 500 feet but that he was not ‘in the slot’ because his airspeed was too high, the report stated. “He indicated that he became ‘fixated on the runway,’ and he could not explain why he did not perform a go-around maneuver.”

Comments like this can come out due to no fear of criminal persecution... In Indonesia, as long as the threat of criminal persecution, no matter how good-willed the crew is regarding the investigation, I doubt that these kinds of comments would come out... such is the sadness of the situation.

Mandala499
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RE: Indonesian B737 Crash, Part 3

Thu Mar 22, 2007 7:20 pm

Quoting Mandala499 (Reply 43):
New rumours now surfacing here that the airplane came at 205kts at flap5... which is something I don't agree with given the flaps he aircraft ended up with.

Thanks, Mandala - don't know where we'd be without you being on the spot with an ear to the ground. But I suspect that, if negligence on that sort of scale is even possibly involved, it'll be a long time before we hear anything more from offical sources.

About 'how much flap,' to my mind 'when' is as important, even more important, than 'if.' 205 knots and five degrees flap (plus gear down) would be about right as they started the approach. On the other hand, 205 knots and only 5 degrees of flap as they crossed the runway threshold would just about qualify as attempted suicide (or murder), if they then went on trying to land.

And, as I've said, and subject to the opinion of jet pilots, adding more flap at that late stage would be counter-productive as it would generate more lift when they least needed it, and actually increase the tendency to 'float' and/or bounce.

I do begin to wonder if the pilots made the most amateur of mistakes - thought that the purpose of flaps was to slow the aeroplane down. It isn't, of course - any slowing down is a by-product of increased drag. The purpose of flaps is to increase the wing area/lift so that the aeroplane can fly safely at a lower speed.

[Edited 2007-03-22 12:28:30]
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md80fanatic
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RE: Indonesian B737 Crash, Part 3

Thu Mar 22, 2007 10:14 pm

Quoting NAV20 (Reply 44):
And, as I've said, and subject to the opinion of jet pilots, adding more flap at that late stage would be counter-productive as it would generate more lift when they least needed it, and actually increase the tendency to 'float' and/or bounce.

There is much here you are leaving out...whether on purpose or not.

Consider a situation where the PF fully opened the spoilers while advancing the flaps from 5 to whatever. The further the flaps extended from their stowed position, the larger the "hole" in the wing becomes. A closed spoiler is the only thing preventing high pressure air from below the wing from invading the crucial low pressure area above the wing.....which is entirely responsible for lift. In this situation.....the further the flaps are extended....the more drag that is induced while the associated additional lift is "spoiled" away through the hole.

This cannot happen on your Cessna, as the flaps simply drop down on a hinge attached to the trailing edge. On the 737, the flaps move away from and down below the wing trailing edge on an arc type path, leaving a hole a person could climb through once the flaps are at full extension.
 
nwafflyer
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RE: Indonesian B737 Crash, Part 3

Fri Mar 23, 2007 7:13 am

Is there any way (Or am I totally out of line) to summarize what we think:

1 - facts that we know
2 - things we suspect are facts
3 - logical conclusions

I have a total respect for Mandala, for Nav20, for Curmudgeon, and while I am not part of this post, I am extremely interested in the outcome of these posts, so I would respectfully like to be included.
 
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RE: Indonesian B737 Crash, Part 3

Fri Mar 23, 2007 8:42 am

Nwafflyer, we'd all love to help if we could; but unfortunately there are very few established facts yet. In addition, there's an 'Item 4' which would have to be added to your list - '4. Alternative theories which might explain what appears to have happened.'

As far as facts are concerned, If you read the first dozen or so posts on this thread, you'll know most of them.

But then along comes some new information. On the basis of the flap position when the aeroplane came to rest, most of us have been assuming that the approach was made with 15 degrees of flap (which in turn suggests an approach speed in the 160-180-knot range). The pilots have complained (among other things) about a 'flap malfunction', which 'suggests' (you can put it no higher than that) that they tried to lower more flap (I believe the options on the 737 are 20, 25, 30, or 40 degrees) but were unable to do so. For information, 30 degrees and maybe 140 knots would be 'normal' for a 737 on final approach.

But now Mandala (who is on the spot and appears to have good local sources) raises the possibility that the flaps were only at 5 degrees, and the speed was no less than 205 knots. But, as I pointed out, this would be normal as the aeroplane began its descent - totally abnormal if that was the situation on final. So we need to know 'when' as well as 'whether.'

The only 'facts' we can be reasonably sure of, from witnesses, are that the aeroplane came in faster than normal, and higher than normal, and landed quite a long way down a relatively-short runway. We're really no wiser, at this point, on WHY that happened.

We may in fact not know the answers to most of the questions for years yet. That's normal in crash investigations, an awful lot of facts have to be checked and evaluated by the investigators, and a long detailed report has to be prepared. In addition, as Mandala points out, in this case there is the possibility of criminal prosecution. In the United States the investigators can afford to be a little more forthcoming, because there is a statutory prohibition on Safety Board information being used as evidence in any court; but I don't expect that Indonesia has any similar provision.

On the other hand, the investigators now appear to have information from both the Flight Data Recorder and the Cockpit Voice Recorder. They must be a long way down the road of reconstructing WHAT happened, but not necessarily WHY. But that doesn't mean that they'll be able to publish that information, even if they wanted to (except that one would expect that they will pass on any information bearing on aircraft safety to airlines and manufacturers, on a confidential basis).
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tetuko
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RE: Indonesian B737 Crash, Part 3

Fri Mar 23, 2007 10:14 am

Mandala,

An asymmetric flaps/slats deployment means, by definition, that the left and right flaps/slats do not deploy to the same position.

The pilots will know and feel it if the flaps deployed asymmetrically. Try it in the simulator (and no, NOT MSFS).

As to your rumor, the pilots would not be so stupid as to be at the threshold with 205 knots on the clock. They MIGHT be in error in not electing to go around, but they are not idiots. They are not that stupid.

Anyway, how can anybody determine that it was at 205 knots? Why not 207? Or 200? Did he/she have a radar gun or something?

While there is the possibility that the flaps did not come down to the 30 degrees position when it was selected to by the pilots, I do not believe that that was the case. The pilots will feel it through the aircraft's behaviour.

We do not know what final position the flaps are in. It may be already at 30 deg, only to appear not to because of the aircraft's journey plowing through the embankment and then the rice paddies.

There is the very small possibility that the flaps are not at the 30 deg position was because the crew was really rushing the approach and that flaps 30 was either never selected (missed), selected late, or simply did not get deployed because the aircraft was never at the airspeed where flaps 30 can be selected.

For me, I do not think that a flap problem had anything to do with this accident.
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NAV20
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RE: Indonesian B737 Crash, Part 3

Fri Mar 23, 2007 10:43 am

Quoting Tetuko (Reply 48):
Anyway, how can anybody determine that it was at 205 knots? Why not 207? Or 200? Did he/she have a radar gun or something?

The investigators have had the information from the Flight Data Recorder for some time. They will know the airspeed ('indicated,' anyway) AND the flap positions for each stage of the approach. According to press reports, they now have the Cockpit Voice Recorder transcript as well.

Quoting Tetuko (Reply 48):
There is the very small possibility that the flaps are not at the 30 deg position was because the crew was really rushing the approach and that flaps 30 was either never selected (missed), selected late, or simply did not get deployed because the aircraft was never at the airspeed where flaps 30 can be selected.

Conforms to my own view, on the evidence so far. Except that I don't think that the possibility is 'very small.'

But I hasten to add that while we may know (or be able to deduce) a bit about 'what,' we still know precious little about 'when', and nothing at all about 'why.'
"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci